A student is learning about hormonal communication in the human body. Explain how a hormone produced by a gland reaches its target organ and brings about a response. In your answer, include how hormonal communication differs from nervous communication in terms of speed and duration of response.

OCR A-Level Biology B — Advancing Biology (H422) — 5.8 Hormonal communication · Explain · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Hormones are chemical messengers secreted by glands directly into the bloodstream. They travel to target organs, where they cause a response. The endocrine system works alongside the nervous system to coordinate body functions.

Model answer (5 marks)

Hormones are secreted by endocrine glands and released directly into the bloodstream.
They travel through the blood to reach their target organ.
Only the target organ responds because it possesses specific receptors that match the hormone.
Hormonal communication is slower than nervous communication.
The responses produced by hormones last longer than those produced by nerves.

Examiner tips

  • Use the exact terminology: endocrine glands, bloodstream, specific receptors, slower, longer duration
  • Structure answer in five clear points matching the scheme
  • Mention speed and duration differences explicitly

Common mistakes

  • Confusing endocrine with exocrine glands
  • Lumping all receptors as ‘complementary’ instead of ‘specific’
  • Omitting the comparison of speed and duration

Mark scheme (5 marks)

  1. Hormones are secreted by (endocrine) glands / released into the bloodstream
  2. Hormones travel in the bloodstream to the target organ
  3. Only the target organ responds because it has (complementary / specific) receptors for that hormone
  4. Hormonal communication is slower than nervous communication
  5. Hormonal responses last longer / have a longer duration than nervous responses

Key terms in this question

hormone · gland · target organ

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